This invention relates to a display method and apparatus for navigation system for displaying information necessary for guiding a driver of a vehicle, and more particularly, to a display method and apparatus for navigation system for displaying information in different forms and contents depending on whether the vehicle is in motion or stationary.
A vehicle navigation system performs vehicle travel guidance for enabling a driver to easily drive the vehicle to a selected destination. Such a navigation system detects the position of the vehicle, reads out map data pertaining to an area at the vehicle current position from a data storage medium, for example, a CD-ROM (compact disk read-only memory) or a DVD (digital videodisc), and displays a map image on a monitor (display) screen while superposing a mark representing the current location of the vehicle on a predetermined portion of the map image.
The vehicle position is determined by a self-contained navigation sensors (e.g. a distance traveled sensor and a bearing sensor) mounted in the vehicle or by a global positioning system (GPS) including a satellite (satellite navigation). The satellite navigation enables absolute position detection and higher position accuracy than the self-contained navigation sensors. However, the satellite navigation involves problem of position detection failure such as in a tunnel or a building where the satellite radio signals are obstructed. Therefore, recent navigation systems utilize both self-contained navigation and satellite navigation to achieve improved performances.
As the present position of the vehicle changes with the travel of the vehicle, the vehicle current position mark in the map image on the screen is changed accordingly. Alternatively, the map is scrolled while the vehicle current position mark is fixed at a predetermined position, for example, at the center of the image. In either methods, the navigation system enables the driver to recognize the map information of the area at the vehicle position at a glance.
When a destination is not set, such a navigation system functions as a locator map which indicates the current location of the vehicle in a map image. When the destination is set, the navigation system starts a route guidance function for setting a guided route from the starting point to the destination. Typically, the route guidance function performs an intersection guidance process in which a monitor screen displays an enlarged intersection diagram and the direction in which the vehicle is to travel while displaying the guide route on a map. When a starting point and a destination are input, a CPU in the navigation system automatically determines a most suitable guided route and successively stores nodes (expressed in longitude and latitude) constituting the guided route in a memory.
During actual traveling, the node series stored in the memory is searched for a portion of the guided route to be displayed in a map display area of the monitor screen, and the portion of the guided route is highlighted so as to be discriminable from other routes. When the vehicle is within a predetermined distance of an intersection it is approaching, an intersection guidance diagram (an enlarged or highlighted intersection diagram with an arrow indicating the direction in which the vehicle is to turn at the intersection) is displayed to inform a driver of the desired one of roads or directions selectable at the intersection.
FIG. 1A shows an example of a locator map display containing a vehicle current position mark VCP on a map image 21. Typically, a navigation system highlights the street on which the vehicle is running in the map image 21 and shows a name of the street such as xe2x80x9cW 190TH STxe2x80x9d in an information box 23 on the display screen. Other information such as a north pointer NP, a map scale and a current time may also be illustrated on the display screen. In this manner, the locator map display shows the current position of the vehicle on the map image, however, it does not perform the route guidance function because the destination is not set in the navigation system.
FIG. 1B shows an example of route guidance display which performs the route guidance function. The route guidance display is activated after specifying the destination of travel. In addition to the map image 21 similar to the locator map of FIG. 1A, this example further shows an arrow indicating the direction (left) in which the vehicle is to turn at the intersection in a guidance information box 22 at the top of the screen. The guidance information box 22 also shows a name of the street xe2x80x9cPREIRIE AVExe2x80x9d which intersects with the current street xe2x80x9cW 190TH STxe2x80x9d and a distance to the intersection. Thus, the navigation system indicates that the vehicle should make a left turn at the intersection with xe2x80x9cPREIRIE AVExe2x80x9d. Typically, the current street xe2x80x9cW 190TH STxe2x80x9d and the left side of the street xe2x80x9cPREIRIE AVExe2x80x9d will be highlighted in the map image 21. Further, such route guidance is accompanied by spoken instructions. If the direction of travel in the next intersection is left, the navigation system gives spoken guidance such as xe2x80x9cturn left at the next intersectionxe2x80x9d. In this example, an information box 24 at the bottom of the display screen includes information regarding the remaining distance to the final destination and an estimated time to reach the final destination.
In order to be guided by the route guidance mode such as shown in FIG. 1B, a destination must be specified in the navigation system so that the system can find one or more routes to get to the destination. FIGS. 2A-2F show examples of display shown on the screen during the operation of inputting the destination.
By operating a menu key, a main menu 25 such as shown in FIG. 2A is displayed on the navigation system and a menu item xe2x80x9cDestinationxe2x80x9d is selected from the main menu. This allows the navigation system to display a xe2x80x9cEnter Destination byxe2x80x9d menu 27 as shown in FIG. 2B for specifying an input method for selecting the destination. The xe2x80x9cEnter Destination byxe2x80x9d menu 27 lists various methods for selecting the destination including xe2x80x9cAddressxe2x80x9d for specifying the city and address of the destination, xe2x80x9cIntersectionxe2x80x9d for specifying the names of two streets in the city which intersect with one another, and xe2x80x9cPoint of Interestxe2x80x9d for selecting the programmed destination based on the category or telephone number. Other methods in the xe2x80x9cEnter Destination byxe2x80x9d menu 27 include xe2x80x9cRecent Routexe2x80x9d for specifying the destination based on the recent destinations saved in the navigation system, xe2x80x9cAddress Bookxe2x80x9d for selecting the address of the destination out of the addresses stored in the system, and xe2x80x9cMap Cursorxe2x80x9d for specifying the destination by pointing a cursor to the destination on the map.
When selecting the xe2x80x9cPoint of Interestxe2x80x9d in FIG. 2B, the navigation system displays a xe2x80x9cCategory Listxe2x80x9d menu 28 such as shown in FIG. 2C. The xe2x80x9cCategory Listxe2x80x9d menu 28 contains various different categories such as xe2x80x9cBankxe2x80x9d, xe2x80x9cRestaurantxe2x80x9d, xe2x80x9cHotelxe2x80x9d, xe2x80x9cShoppingxe2x80x9d and others. Supposing the category xe2x80x9cShoppingxe2x80x9d is selected, the navigation system displays a xe2x80x9cName Listxe2x80x9d such as shown in FIGS. 2D and 2E. The xe2x80x9cName Listxe2x80x9d shows names of shops and shopping malls sorted by, for example, distance from the vehicle. In an address information box 31 on the display, the address and phone number of the highlighted name in the list 33 will be displayed. The address information box 31 may also show the distance to the highlighted shop. Typically, the navigation system stores several tens or hundreds of names of shops within predetermined distances and displays several shops per page of display screen, and a user may scroll the display screen to see other names of shops in the name list 36 such as shown in FIG. 2E.
When the destination is not prestored in the navigation system, a user can input the destination by selecting, for example, the xe2x80x9cAddressxe2x80x9d method or xe2x80x9cIntersectionxe2x80x9d method in the xe2x80x9cEnter Destination byxe2x80x9d menu 27 of FIG. 2B. Then, the navigation system displays an xe2x80x9cEnter Street Namexe2x80x9d shown in FIG. 2E for inputting the city and address in an address input box 37 by means of a key board 38 displayed on the display screen.
After inputting the destination, the navigation system determines a route to the destination based on, for example, by finding the shortest way to reach the destination. In the conventional navigation system, the foregoing process of specifying the destination can be done either the vehicle is running or stationary. While driving, a driver may want to change the destination or to set a new destination after reaching the original destination.
As noted above, the operation of the navigation system, such as inputting the destination, requires the driver to look at the information on the display screen such as shown in FIGS. 2A-2C, or scroll the display such as shown in FIGS. 2D and 2E, or even input the destination through the key board such as shown in FIG. 2F. Thus, the navigation system may distract the driver""s attention from safe driving. Therefore, for maintain safe driving, it is necessary to simplify the operation of the navigation system while the vehicle is in motion. In the industry, there is an unofficial rule that an operation of a navigation system by a driver must be done less than fifteen seconds.
It is, therefore, an object of the present invention to provide a display method and apparatus for vehicle navigation system which enables a driver to operate the navigation system within a short period of time without inversely affecting the driving of the vehicle.
It is another object of the present invention to provide a display method and apparatus for vehicle navigation system which displays information in different forms and contents depending on whether the vehicle is in motion (running) or stationary (standing still).
It is a further object of the present invention to provide a display method and apparatus for vehicle navigation system which is able to specify the destination of travel by a smaller number of key movements (clicks) when the vehicle is in motion than that when the vehicle is stationary.
The display method and apparatus of the navigation system is designed to promote safe driving by differentiating display formats and contents depending on whether the vehicle is in motion or stationary. When the vehicle is stationary, the navigation system can perform all of the functions. However, when the vehicle is in motion, the navigation system provides simplified and limited functions to ease the operations. The number of key strokes required for operating the navigation system is reduced when the vehicle is in motion.
In one aspect of the present invention, a display method of a vehicle navigation system includes steps of detecting whether a vehicle is in motion or stationary and sending a corresponding signal to a controller of the navigation system, changing a display screen of the navigation system to an in-motion main menu when the vehicle is in motion and a menu key is pressed by the driver, changing the display screen of the navigation system to a stationary main menu when the vehicle is stationary and the menu key is pressed by the driver. The in-motion main menu displays an item list showing less than a predetermined number, for example ten, of items in one page of a display screen in which the items are limited to methods for specifying a destination of travel.
In the in-motion main menu or other menus displayed when the vehicle is in motion, a display scroll function for the menus is disabled. Further, in the in-motion main menu or other menus displayed when the vehicle is in motion where each of the menus lists a plurality of items, an initial highlight position is on an item at about a middle point of the item list.
In the further aspect, the display method of the present invention includes a step of displaying a locator map screen when the destination of travel is not set in the navigation system, wherein the locator map screen displays a map image of an area within a predetermined distance from the vehicle and a vehicle current position mark in the map image showing a current position of the vehicle and a street image on which the vehicle is running.
In a further aspect of the present invention, the display method of the present invention includes a step of displaying a route guidance screen when the destination of travel is set and an appropriate route to the destination is determined by the navigation system, wherein the route guidance screen displays a map image of an area within a predetermined distance from the vehicle and a vehicle current position mark in the map image showing a current position of the vehicle, an image of a current street on which the vehicle is running, a name of a cross street on which the vehicle is to make a turn, and a direction of the turn on the cross street.
A further aspect of the present invention is a display apparatus of a vehicle navigation system. The display apparatus includes means for detecting whether a vehicle is in motion or stationary and sending a corresponding signal to a controller of the navigation system, means for changing a display screen of the navigation system to an in-motion main menu when the vehicle is in motion and a menu key is pressed by the driver, means for displaying in-motion break down menus specifically made for use when the vehicle is in motion where the break down menus starts from the in-motion main menu, means for changing the display screen of the navigation system to a stationary main menu when the vehicle is stationary and the menu key is pressed by the driver, and means for displaying stationary break down menus made for use when the vehicle is stationary where the stationary break down menus starts from the stationary main menu. Each of the in-motion main menu and the in-motion break down menus displays an item list in one page of a display screen for which a display scroll function is disabled when the vehicle is in motion.
According to the present invention, the display method and apparatus for vehicle navigation system enables the driver to operate the navigation system within a short period of time without inversely affecting the safe driving of the vehicle. The vehicle navigation system displays information in different forms depending on whether the vehicle is in motion or stationary. The navigation system is able to specify the destination of travel by a small number of key movements when the vehicle is in motion.